System and method for discontinuous reception control start time

ABSTRACT

Methods of combining semi-persistent resource allocation and dynamic resource allocation are provided. Packets, such as VoIP packets, are transmitted on the uplink and downlink using respective semi-persistent resources. For each mobile device, awake periods and sleep periods are defined. The semi-persistent resources are aligned with the awake periods so that most of the time the mobile device can turn off its wireless access radio during the sleep periods. In addition, signalling to request, and to allocate, resources for additional packets are transmitted during the awake periods, and the resources allocated for the additional packets are within the awake periods. Methods of extending the awake periods in various embodiments are also provided. Methods of determining the first on period are also provided.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/287,731 filed Nov. 2, 2011, which is a continuation of U.S. patentapplication Ser. No. 11/957,624 filed Dec. 17, 2007, which claimspriority to U.S. Provisional Application No. 60/972,583 filed Sep. 14,2007, the applications are hereby incorporated by reference in theirentirety.

FIELD OF THE APPLICATION

The application relates to wireless communication, and more particularlyto transmission scheduling for wireless communication.

BACKGROUND

With semi-persistent scheduling, for downlink VoIP (voice over IP(Internet Protocol)) communications to a mobile device, a periodic DL(downlink) transmission resource is allocated during a talk-spurt on thedownlink. The same resource is allocated each time. The allocation isturned on during each of the talk-spurts and off between talk-spurts. Inthis manner, explicit signalling to request an allocation, and to granta particular VoIP allocation is not required. Semi-persistent schedulingfor uplink VoIP communications from a mobile station is similar.

In addition to regular VoIP traffic, mobile devices also need theability to send and transmit larger IP packets. Such larger IP packetsare likely to be relatively infrequent compared to the frequency ofregular VoIP transmissions. Such packets might include uncompressed IPpackets, RTCP (Remote Transmit Power Control) packets, SIP/SDP (SessionInitiation Protocol/Session Description Protocol) packets, etc. Such IPpackets may be several hundreds of bytes in size and may have highpriority. In addition, larger packets may be required to transmit RRC(Radio Resource Control) Signalling messages. Examples of this arehandover related messages such as measurement reports. Some mobiledevices will also need the ability to deliver a mixed service in whichcase services in addition to VoIP need to be provided to the mobiledevice, such as e-mail, web browsing etc.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described with reference to the attacheddrawings in which:

FIG. 1 is a signalling diagram showing dynamic scheduling vs.semi-persistent scheduling;

FIG. 2 is a block diagram of an example wireless system;

FIG. 3 is a signalling diagram showing an awake period for dynamicscheduling in DRX (discontinuous reception);

FIG. 4 is a signalling diagram showing DRX and DTX (discontinuoustransmission) for uplink and downlink;

FIG. 5 is a state diagram having DRX and DTX transitions for VoIP;

FIGS. 6 and 7 are flowcharts of methods executed by a network to performcombined semi-persistent and dynamic scheduling;

FIGS. 8 and 9 are flowcharts of methods executed by a mobile device toperform combined semi-persistent and dynamic scheduling;

FIG. 10 is a block diagram of a mobile device;

FIG. 11 is a flowchart of a method for a network to determine a starttime for discontinuous reception control;

FIG. 12 is a flowchart of a method for a network to determine a starttime for discontinuous reception control;

FIG. 13 is a flowchart of a method for a network and mobile station todetermine a start time for discontinuous reception control in which thenetwork transmits signalling to the mobile device; and

FIG. 14 is a flowchart of a method for a network and mobile station todetermine a start time for discontinuous reception control in which theboth the network and the mobile device access default parameters todetermine the first on period.

DETAILED DESCRIPTION OF EMBODIMENTS

According to one broad aspect, the application provides a method in anetwork for the network to provide wireless communications to a mobiledevice, the method in the network comprising: transmitting by thenetwork discontinuous reception control parameters to a mobile device,the discontinuous reception control parameters indicating periods duringwhich the mobile device will have its receiver powered on oncediscontinuous reception control is active; determining by the network afirst of said periods during which the mobile device will have itsreceiver powered on and after which discontinuous reception control willbe active; and transmitting by the network to the mobile device inaccordance with the discontinuous reception control parameters startingwith the first of said periods.

According to another broad aspect, the application provides a method ina mobile device for the mobile device to receive wireless communicationsfrom a network, the method in the mobile device comprising: receiving bythe mobile device discontinuous reception control parameters from thenetwork, the discontinuous reception control parameters indicatingperiods during which the mobile device will have its receiver powered ononce discontinuous reception control is active; determining by themobile device a first of said periods during which the mobile devicewill have its receiver powered on and after which discontinuousreception control will be active; and receiving by the mobile devicecommunications from the network in accordance with the discontinuousreception control parameters starting with the first of said periods.

According to another broad aspect, the application provides an apparatusfor providing communications services to a mobile device, the apparatuscomprising: a DRX (discontinuous reception) controller that determinesdiscontinuous reception control parameters for a mobile device, thediscontinuous reception control parameters indicating periods duringwhich the mobile device will have its receiver powered on oncediscontinuous reception control is active; the DRX controller beingfurther configured to determine a first of said periods during which themobile device will have its receiver powered on and after whichdiscontinuous reception control will be active; and a transceiver and atleast one antenna for establishing a wireless link with the mobiledevice, the transceiver being used to transmit the discontinuousreception control parameters to the mobile device and to transmit to themobile device in accordance with the discontinuous reception controlparameters starting with the first of said periods.

According to another broad aspect, the application provides a mobiledevice comprising: a wireless access radio for receiving wirelesscommunications from a network; a radio manager that controls when thewireless access radio is on and when the wireless access radio is off;the radio manager configured to perform the control of the wirelessradio access in accordance with discontinuous reception controlparameters from the network via the wireless access radio, thediscontinuous reception control parameters indicating periods duringwhich the mobile device will have its receiver powered on oncediscontinuous reception control is active; and the radio manager furtherconfigured to determine a first of said periods during which the mobiledevice will have its receiver powered on and after which discontinuousreception control will be active such that the mobile device receivesfrom the network in accordance with the discontinuous reception controlparameters starting with the first of said periods.

Further embodiments provide computer readable media having computerexecutable instructions stored thereon, for execution by a wirelessdevice or network device for example, that control the execution of oneor more of the methods summarized above, or described below.

Dynamic scheduling has been proposed to allow the dynamic allocation oftransmission resources, and the subsequent transmission of a largepacket using the dynamically allocated resources. Dynamic schedulinginvolves allocating a resource each time a packet is to be transmitted,and the resource can differ for each allocation. In a particularexample, see Applicant's co-pending U.S. Provisional Patent ApplicationNo. 60/944,367 filed on Jun. 15, 2007 and hereby incorporated byreference in its entirety.

In a specific example, a mobile device supporting VoIP with dynamicscheduling monitors layer 1 CCEs (Control Channel Elements) continuouslyfor dynamic scheduling grants even though the mobile device might beonly involved in a VoIP session. LTE (Long Term Evolution) refers toCCEs, but the term has more general application to mean simply controlinformation.

As indicated above, a mobile device may support VoIP with dynamicscheduling by monitoring layer 1 CCEs continuously for dynamicscheduling grants. Unfortunately, this might waste battery power for themobile device, particularly when there are very few or even no dynamicscheduling grants for the mobile device.

Referring now to FIG. 1, shown is a signalling diagram showing dynamicscheduling vs. semi-persistent scheduling. Time is on the horizontalaxis. Shown is a periodic semi-persistent allocation 50. For VoIPtransmission, this can for example include a resource allocated every 20ms. In addition, there is a regular set of layer 1 CCEs 52 that aretransmitted. In the illustrated example, these are transmitted in every1 ms but it is to be clearly understood that the other resourceallocation periods and CCE periods are possible. This example assumesdownlink transmission, but a similar approach applies to uplinktransmission. During the periods that occur between talk-spurts, (alsoreferred to as “silence” or “silence periods”), the transmitter andreceiver can be turned off. During a talk-spurt period (also referred toas a period that VoIP transmission is “active”, or “active mode”), ifnot for dynamic scheduling, the mobile device could wake up regularly toblind-detect its data in the semi-persistently allocated resource at thepre-defined interval (e.g. every 20 ms) while entering a “sleeping” modeat other times. This can also be referred to as DRX (discontinuousreception). This simply means that the receive capability of the mobiledevice's radio is basically turned off while the mobile device is insleep mode thereby resulting in battery life extension. However, giventhat other data may arrive via dynamic scheduling by any of the CCEs 52,the mobile device needs to monitor the CCEs of all sub-frames. In thefull dynamic scheduling case there is no DTX or DRX and this rules outthe possibility of using DRX since the mobile device needs to continuemonitoring the layer 1 CCEs for dynamic scheduling grants for possibledata coming. This is not power efficient and leads to lower batterycharge lifetimes.

To efficiently support the DRX in VoIP active mode in order to reducethe battery power consumption, systems and methods are provided forcombining semi-persistent scheduling for VoIP with a schedulingcapability for additional packet transmission. These methods areparticularly effective for a mobile device that is only involved in aVoIP session (i.e. not requiring mixed service).

System for Semi-persistent Scheduling and DRX Control

Referring now to FIG. 2, shown is a block diagram of an example wirelesssystem 40. The wireless system 40 has a wireless network 28 and a mobiledevice 10. The wireless system also has other mobile devices 30.

The mobile device 10 has a wireless access radio 12, a processor 16 anda radio manager 14 that is responsible for controlling the wirelessaccess radio 12 and performing radio resource control. There may beadditional components not shown. The radio manager 14 may be implementedin software running on appropriate hardware, hardware, firmware orcombinations thereof.

The wireless network 28 has a scheduler 32 that encompasses asemi-persistent scheduler 34 and a dynamic scheduler 36. The wirelessnetwork 28 has components such as base stations (not shown) forproviding wireless access. These include a transceiver 31 having atleast one antenna 33. The scheduler 32 may reside in a base station orelsewhere in the network 28. In LTE, the scheduler is typically in theeNB (enhanced NodeB). In the examples that follow, it is assumed thatscheduler 32, transceiver 31 and antenna 33 are all parts of a basestation. Also shown is a DRX controller 29 that is responsible forsetting up/configuring/obtaining knowledge of the DRX behaviour for eachmobile device. The DRX controller 29 may be part of a base station andmay be implemented in software running on appropriate hardware,hardware, firmware or combinations thereof.

In the illustrated example, the scheduler 32 and radio manager 14 areimplemented as software and executed on processors forming part of thenetwork 28 and mobile device 10 respectively. However, more generally,these functions may be implemented as software, hardware, firmware, orany appropriate combination thereof.

Furthermore, it is to be understood that the wireless network would haveany appropriate components suitable for a wireless network 28. Note thatthe wireless network may include wires that interconnect networkcomponents in addition to components for providing wirelesscommunication with mobile devices. The components of the wirelessnetwork are implementation specific and may depend on the type ofwireless network. There are many possibilities for the wireless network.The wireless network might for example be a UMTS network or any cellularnetwork that uses semi-persistent resource assignment.

In operation, the mobile device 10 communicates with the wirelessnetwork 28 over a wireless connection 19 between the mobile device 10and the wireless network 28. The communication with the wireless network28 includes VoIP packet transmission and additional packet transmission.The semi-persistent scheduler 34 is responsible for making an initialresource allocation for a VoIP service to the mobile device 10. Thisincludes an uplink semi-persistent allocation and a downlinksemi-persistent allocation. The semi-persistent scheduler 34 is alsoresponsible for keeping track of whether there is a talk-spurt inprogress for the uplink and/or the downlink and for turning on and offthe uplink and/or downlink allocation accordingly. While de-allocated,the semi-persistently allocated resources can be made available forother purposes. Note that the form of the transmission resources thatare being allocated is implementation specific. Particular examples ofresources that might be used include OFDM resources and CDMA resources.The dynamic scheduler 36 is responsible for making resource allocationsfor additional packet transmissions that are not accommodated by thesemi-persistent allocation. The additional packets may be related toand/or form part of the VoIP service, or be unrelated to the VoIPservice.

The radio manager 14 controls the on/off state of the wireless accessradio 12. In some wireless access radios, the transmitter and receivermust be turned on and off together, and as such, uplink and downlinkscheduling must be coordinated to allow the wireless access radio to beturned off. In some wireless access radios, receive and transmitcapabilities can be independently turned off.

In some embodiments, the network 28 sends DRX control signalling to themobile device 10 that sets a repeating pattern that has a DRX periodhaving an awake period and a sleep period. An example could be: DRXperiod is 20 ms with sleep period equal to 15 ms and awake period equalto 5 ms. During the awake period, the mobile device turns its receiveron. During the sleep period, the mobile device turns its receiver off.This signalling might be sent at the start of each VoIP session, forexample.

In some embodiments, the DRX controller 29 transmits DRX controlparameters to the mobile device to set up DRX control. In addition, theDRX controller 29 determines when DRX control is to start. Specificexamples are provided below under the heading “Controlling the Start ofDRX Control”. In some embodiments, the DRX controller is a piece of basestation software running on a processor in a base station that controlsthe DRX procedure. It may be incorporated into the base station radioresource control software or radio resource management software.

In the mobile device 10, the wireless access radio 12 receives wirelesscommunications from the network 28. The radio manager 14 controls whenthe wireless access radio 12 is on and when the wireless access radio isoff in accordance with DRX control parameters received from the network.Specific detailed examples are provided below. In addition, the radiomanager further 14 is further configured to determine a first of theperiods during which the mobile device will nominally have its receiverpowered on and after which discontinuous reception control will beactive such that the mobile device receives from the network inaccordance with the discontinuous reception control parameters startingwith the first of said periods. Various detailed examples are providedbelow under the heading “Controlling the Start of DRX Control”.

Referring now to FIG. 3, shown is a signalling diagram showing anexample of semi-persistent and dynamic scheduling and DRX. Shown is asemi-persistent allocation 60 available for semi-persistent VoIP DLtransmissions. In addition, there are layer 1 CCEs 62 for signallingdynamic allocations so as to allow the transmission of additionalpackets. This represents the transmissions from the base station. Themobile device receiving the transmissions alternates between being in anawake state and a sleep state. The mobile station is in an awake stateduring awake periods 64 and the mobile device is nominally in a sleepstate during sleep periods 66. The first thing that the scheduler in thenetwork needs to do is to ensure that the semi-persistent allocation 60coincides with the awake periods 64. In addition, each awake period 64is longer than the minimum necessary to transmit the VoIPsemi-persistent allocation. There is also the opportunity to dynamicallyschedule (as signalled on one of the CCEs 62) and transmit an additionalpacket. An example of this is shown where a dynamic allocation issignalled in CCE 62-1. Additional packet 67 is shown transmittedimmediately following CCE 62-1. The additional packet might for examplebe an RTCP packet, SIP/SDP packet, or a packet that has not undergoneIP\UDP\RTP header compression, etc. While the mobile device is in thesleep state, it operates in a reduced power consumption mode, by turningoff reception capability and/or by turning off its reception andtransmission capabilities. In this example, the network has scheduledthe additional packet 67 to be transmitted during one of the awakeperiods 64, and signals this using a CCE 62-1 that is transmitted duringone of the awake periods 64. More generally, when the mobile devicewakes up after a sleep period, the mobile device will not only blinddetect its own VoIP data on the semi-persistently allocated resource 60,but also will detect, more generally attempt to detect, all the CCEsduring the awake periods.

In some embodiments, after the mobile device determines that there willbe a dynamically allocated resource for the mobile device as signalledin one of the CCEs in a given awake period, the mobile device does notmonitor further CCEs during that awake period.

In some embodiments, the base station will transmit signalling toconfigure the mobile device with this DRX behaviour, and thereafter allthe dynamic scheduling will occur only in this “awake period”. Forexample, the mobile device may sleep every 15 ms, and then wake up for 5ms to continuously receive data. The behaviour repeats with a period of20 ms. During the 5 ms awake period, the mobile device will blind-detectits VoIP data on the semi-persistently allocated resource and also themobile device will monitor all the CCEs. The base station understandsthis DRX configuration and will schedule the associated dynamic packetssuch as RTCP, SIP/SDP, etc, during this 5 ms awake period. In someimplementations, when a retransmission occurs, the mobile device will bein continuous mode by default.

The radio manager 14 controls the operation of the wireless access radio12 such that a reception capability is powered on during the awakeperiods, and off for at least some of the sleep periods. As describedbelow, it may be necessary for the reception capability to be on duringsome of the sleep periods to allow for retransmissions.

The signalling for dynamic scheduling is performed during the awakeperiods. In addition, the actual resources allocated for the additionalpacket transmissions are scheduled to occur during the awake periods.

In some embodiments, when it becomes necessary for a retransmission, themobile device enters a continuous mode of operation. While in continuousmode, the mobile device continuously receives and monitors the downlinkchannel and does not turn off reception capability. Further, in someembodiments, if a mixed service needs to be provided to the mobiledevice, this is used as a trigger to also enable the continuous modeoperation. This trigger may be dependent on the traffic QoS of theservice being added.

Uplink Semi-persistent Alignment with Downlink for DRX

The above discussion is focussed on downlink transmission from the basestation to the mobile device and on the mobile device's ability to turnoff its reception capability during the sleep period. However, somemobile devices are not able to turn off only their reception capabilitywhile leaving on a transmit capability or vice versa. Thus, for suchdevices in order to fully realize the benefit of having an awake periodand a sleep period for reception, uplink transmissions should are alsoscheduled to align with these awake periods and sleep periods. Anexample of this is shown in FIG. 4. In FIG. 4, the downlink transmissionis indicated at 78 and this is basically the same as that describedabove with reference to FIG. 3, and this will not be described again.The uplink transmissions are generally indicated at 80. Here, there is asemi-persistent allocation 82 for VoIP UL transmissions. These arescheduled to occur during the periods 64 that the mobile device isawake. In addition, an uplink control channel is indicated at 84. In theillustrated example, this occurs every lms. The mobile device onlytransmits the uplink control channel during the awake periods 64. Themobile device can use the uplink control channel to make requests foradditional resources. By scheduling the uplink semi-persistenttransmission and downlink semi-persistent transmission to occur duringthe same awake period, the mobile device can realize much more efficientDRX and DTX (discontinuous reception and discontinuous transmission)behaviour. In the example of FIG. 4, the mobile device is configured tosleep every 15 ms, and then wake up for 5 ms. During this 5 ms awakeperiod, the mobile device will receive DL semi-persistent reception ifavailable (during a DL talk-spurt) and make an uplink semi-persistenttransmission if available (during an UL talk-spurt). The mobile devicewill also detect all the DL grants and possibly make uplink additionalresource requests.

In case of retransmissions (either the DL or the UL), the mobile devicewill enter the continuous mode by default. Note that both the uplink anddownlink VoIP semi-persistent allocations have the same trafficcharacteristics (every 20 ms), hence the base station can easily alignthe semi-persistent allocation for the DL and UL.

With this approach, even in the active mode (talk-spurt in progress onthe uplink or the downlink), the mobile device can be in DRX and DTXmode most of the time. The mobile device monitors the Layer 1 CCEs onthe downlink only during the awake period, and may request moreresources on the uplink. This can save battery power for the mobiledevice. Considering that an additional IP packet delivery during a VoIPsession may be infrequent, the battery saving could be significant. Adrawback is that the dynamic scheduling could be delayed by anadditional 10 ms on average.

Referring now to FIG. 5, shown is a state diagram having DRX/DTX statetransitions for VoIP. It is noted that when there is no uplink anddownlink transmission (i.e. silence in both directions), the mobiledevice only needs to monitor the DL CCEs for dynamic scheduling duringthe awake period. There are two main states. The first main state is themobile device sleep state 100 and the second main state is the mobiledevice awake state 102. For the illustrated example, it is assumed thatthe sleep state 100 lasts 15 ms and the awake state lasts 5 ms and canbe extended, but this is again implementation specific. Steps 102-1 and102-2 are executed for downlink communication during the awake state102. Step 102-1 involves receiving all of the downlink CCEs andprocessing them to identify downlink dynamic scheduling if present. Thisis done irrespective of whether or not there is any downlink VoIPtransmission. In the event that a downlink talk-spurt is ongoing, thenstep 102-2 is also executed. This involves receiving the VoIP payload inthe semi-persistent resource. Steps 102-3 and 102-4 are executed inrespect of uplink transmissions. Step 102-3 is only executed if themobile device determines that it needs a dynamic allocation for uplinktransmission. Step 102-3 involves making a resource request, for exampleover a random access channel, and monitoring the downlink CCE for uplinkgrants. In addition, if there is an uplink talk-spurt in progress, thenthe mobile device will execute step 102-4 which involves transmittingthe uplink VoIP payload in the semi-persistent resource for uplinktransmission.

The above description has focussed on applications where the trafficthat is sent using the semi-persistent allocation is VoIP traffic. Moregenerally, the same methods and systems can be applied to combine thetransmission and scheduling of traffic of any type on asemi-persistently allocated resource with the transmission andscheduling of traffic that uses dynamic resource allocations.

In the above examples, CCEs spaced by 1 ms are used for the downlinkcontrol channel. More generally, the downlink control channel can takeany form. The only limitation is that dynamic allocations for a givenmobile device take place during awake periods for the mobile device.Similarly, at least in the figures, the uplink control channel has beendepicted as a random access channel that is available at intervalsspaced by ms. More generally, the uplink control channel for requestingadditional resource allocations can come in any form. The onlylimitation is that requests for dynamic allocations for uplinktransmission from a given mobile device will need to be transmittedduring awake periods for the mobile device.

In some embodiments, the additional packet is transmitted as a series ofone or more sub-packets formed by segmenting the additional packet.These are subject to reassembly at the receiver.

Methods for Semi-persistent Scheduling and DRX Control Executed by theWireless Network

A method in a wireless network for performing downlink transmission tomobile devices will be described with reference to the flowchart of FIG.6. These steps are performed for each mobile device being providedwireless access on a semi-persistent downlink transmission resource. Themethod begins at step 6-1 with transmitting downlink packets to themobile device using a semi-persistent downlink transmission resourcethat is aligned with awake periods defined for the mobile device. Thesecan be downlink VoIP packets during a downlink talk-spurt for a VoIPsession involving the mobile device or otherwise. Steps 6-2,6-3,6-4 areexecuted for each additional downlink packet for the mobile device. Instep 6-2, the wireless network dynamically allocates an additionaldownlink transmission resource to transmit the additional packet, theadditional resource being allocated to occur within one of the awakeperiods defined for the mobile device. In step 6-3, during one of theawake periods defined for the mobile device, the wireless networktransmits signaling that defines the additional downlink transmissionresource to transmit the additional packet. In step 6-4, during one ofthe awake periods defined for the mobile device, the wireless networktransmits the additional downlink packet using the additional downlinkresource. In some embodiments, all of the steps are performed in a basestation. In other embodiments, certain steps, for example the dynamicallocation, can be performed in another network element if centralizedscheduling is performed.

A method in a wireless network for performing uplink reception frommobile devices will be described with reference to the flowchart of FIG.7. These steps are performed for each mobile device being providedwireless access on a semi-persistent downlink transmission resource. Themethod begins with receiving uplink packets from the mobile device usinga semi-persistent uplink transmission resource that is aligned with theawake periods defined for the mobile device. These can be VoIP packetsduring an uplink talk-spurt for a VoIP session involving the mobiledevice or otherwise. Steps 7-2, 7-3, 7-4 and 7-5 are performed for eachadditional each additional uplink packet for the mobile device. In step7-2, during one of the awake periods, the wireless network receives arequest for an additional uplink transmission resource to transmit theadditional uplink packet. In step 7-3, the wireless network dynamicallyallocates the additional uplink transmission resource such that theadditional uplink transmission resource occurs during one of the awakeperiods defined for the mobile device. In step 7-4, during one of theawake periods defined for the mobile device, the wireless networktransmits signaling that defines the additional uplink allocation. Instep 7-5, the wireless network receives the additional uplink packetusing the additional uplink transmission resource.

In some embodiments, the wireless network transmits signaling to eachmobile device that defines the awake periods and that defines sleepperiods of that mobile device and/or that defines the semi-persistentuplink and/or downlink transmission resource of that mobile device. ForVoIP, the signaling to define the semi-persistent resources might bedone at the start of each VoIP session. Such signaling can be performedon a channel that is dedicated to each mobile device, or using abroadcast channel containing such signaling for multiple devices.

Methods for Semi-persistent Scheduling and DRX Control Executed by theMobile Device

Referring now to FIG. 8, a method of receiving downlink transmissionexecuted by a mobile device will now be described. The method begins atstep 8-1 with the mobile device controlling a reception capability ofthe mobile device during a plurality of awake periods and a plurality ofsleep periods, the awake periods alternating in time with the sleepperiods, such that the reception capability is always on during each ofthe awake periods, and the reception capability is off for at least someof the sleep periods. On a nominal basis, typically the receptioncapability will be off for every sleep period. At step 8-2, the mobiledevice receives downlink packets on a semi-persistent downlinktransmission resource that is aligned with a plurality of awake periodsdefined for the mobile device. These can be VoIP downlink packets duringa downlink talk-spurt for a VoIP session involving the mobile device, orotherwise. Steps 8-3 and 8-4 are performed for each additional downlinkpacket for the mobile device. In step 8-3, during one of the awakeperiods, the mobile device receives signaling that defines an additionaldownlink transmission resource to transmit the additional packet, theadditional downlink transmission resource being allocated to occurwithin one of the awake periods defined for the mobile device. In step8-4, during one of the awake periods, the mobile device receives theadditional downlink packet on the additional downlink resource.

The mobile device may receive signaling that defines the awake periodsand the sleep periods of the mobile device and/or that defines thesemi-persistent downlink transmission resource of that mobile device.This may take place over a respective dedicated channel for the mobiledevice or over a broadcast channel containing signaling information forthe mobile device and other mobile devices.

Referring now to FIG. 9, a method of transmitting uplink transmissionsexecuted by a mobile device will now be described. The method begins atstep 9-1 with controlling a transmission capability of the mobile devicesuch that the transmission capability is on during all of the awakeperiods and such that the transmission capability is off for at leastsome of the sleep periods. In step 9-2, the mobile device transmitsuplink packets (VoIP packets or otherwise) using a semi-persistentuplink transmission resource that is aligned with the awake periodsdefined for the mobile device. Steps 9-3, 9-4, 9-5 are executed for eachadditional uplink packet for the mobile device. In step 9-3, during oneof the awake periods defined for the mobile device, the mobile devicetransmits a request for an additional uplink transmission resource totransmit the additional uplink packet. In step 9-4, during one of theawake periods, the mobile device receives signaling that defines theadditional uplink transmission resource, the additional uplinktransmission resource being allocated to occur during one of the awakeperiods defined for the mobile device. In step 9-5, during one of theawake periods, the mobile device transmits the additional uplink packetusing the additional uplink transmission resource.

The mobile device may receive signaling that defines the semi-persistentuplink resource. In some embodiments, the request for an additionaluplink allocation is transmitted using a contention based random accesschannel.

Additional Embodiments

The following variants can be applied in combination with previouslydescribed embodiments.

In some embodiments, the awake period that is aligned with thesemi-persistent resource is provisioned to have a duration that is longenough that it also includes times that the mobile device is expected totransmit/receive an ACK/NACK in respect of a transmission onsemi-persistent resource allocation for the uplink and/or the downlink.In some embodiments, where an ACK/NACK is expected (as will be the casewhen the semi-persistent allocation is active), the awake period isextended to allow for this.

In another embodiment, additional awake periods are provisioned that arealigned with times that the mobile device is expected transmit/receivean ACK/NACK. More specifically, in such embodiments, a DRX/DTX period isprovisioned between an awake period for a voice packet (semi-persistentresource allocation) and an awake period for the ACK/NACK. CCEstransmitted during either of the awake periods can be used to signal adynamic allocation for the uplink and/or downlink. In addition, in someembodiments, during the extended awake period, the mobile device ispermitted to make requests for dynamic allocations for the uplink.

In some embodiments, the sleep period is used for downlinkretransmissions, and the mobile device will have its receptioncapability on in the event a retransmission is expected. Similarly, insome embodiments, the sleep period is used for uplink retransmissions,and the mobile device will have its transmission capability on to allowfor this. The mobile device will not be expecting dynamic allocationsduring such periods. In some embodiments, additional awake periods areconfigured for retransmissions on the uplink and/or downlink. Duringthese additional awake periods, the CCEs can be used to signal possibledynamic allocations. In some embodiments, one or more of the nominalawake periods is made longer so as to allow for thetransmission/reception of retransmissions. In this case, the CCEs of thelonger awake periods are available for dynamic scheduling purposes.

In some embodiments, as described in the detailed examples above, thedynamic allocations are always scheduled to occur during one of theawake periods that are nominally defined with fixed duration. In anotherembodiment, an awake period can be extended to allow for thetransmission/reception of one or more dynamic allocations. For example,a CCE sent during an awake period can allocate a dynamic resourceallocation that occurs partially or entirely outside the awake period,and the mobile device stays powered on to allow that. During the periodthat the mobile device is powered on as a result of the dynamic resourceallocation the mobile device continues to monitor the CCEs, and anadditional CCE signalling another dynamic allocation can be sent and soon.

Controlling the Start of DRX Control

DRX (discontinuous reception) control refers generally to methods ofcontrolling a mobile device to have discontinuous reception capabilityso as to reduce batter consumption. This means there will be periodsthat the mobile device will have its receiver on (an on period, alsoreferred to as an awake period), and periods that the mobile device willhave its receiver off (an off period, also referred to as a sleepperiod). Many different examples of methods of DRX control have beenprovided above.

In accordance with further embodiments, various methods for starting DRXcontrol are provided. Typically one or more DRX parameters are sent tothe mobile device to configure DRX control. These might include one ormore parameters that indicate when the receiver of the mobile devicewill be powered on. They might also include one or more parameters thatindicate an off period duration, although separate signalling to thiseffect might not be necessary if it can be deduced from the signallingthat indicates the on periods. In some embodiments, the parameters alsoindicate an extension period during which the mobile device willcontinue have its receiver powered on following one of said periodsduring which the mobile device will have its receiver powered on ifthere is a dynamic scheduling allocation. These methods may for examplebe implemented by one or both of a DRX controller (such as DRXcontroller 29 forming part of a wireless network 28 of FIG. 2) or aradio manager (such as a radio manager 14 forming part of a mobiledevice 10 of FIG. 2).

It should be apparent from the foregoing that in some embodiments, theperiods that the mobile device will have its receiver on, and theperiods that the mobile device will have its receiver off may be nominalon and off durations respectively, subject to over-ride. In the examplepresented above, the nominal on period can be extended to accommodatedynamic scheduling. Other examples of how the nominal on and offdurations may be varied include for transmitting/receiving ACKs/NACKsand transmitting/receiving retransmissions. Further details of suchexamples can be found in Applicants' co-pending Application No.60/974,653 filed Sep. 24, 2007 hereby incorporated by reference in itsentirety.

Referring to FIGS. 11 and 12, shown are flowcharts of two methods thatare implemented in the network and mobile device respectively.References to steps executed by the network refer to steps that areexecuted by some component(s) in a network, as opposed to the mobiledevice. Examples of network components that might execute one or more ofthese steps include a base station, or an enhanced Node B (ENB). Thesemethods occur in parallel and will be described as such. At step 11-1,the network transmits DRX control parameters to the mobile device. Theseparameters may include parameters that indicate periods during which themobile device will have its receiver powered on, and an extension periodduring which the mobile will continue have its receiver on even at theend of the on period when dynamic scheduling allocation is detected,once discontinuous reception control is active. In some embodiments theparameters also indicate periods during which the mobile device willhave its receiver powered off. They may also include parameters relatingto semi-persistent assignment. They may also include parameters relatingto how larger additional packets are to be handled. These parameters aretypically sent at the start of a communications session between themobile device and the network, for example at the start of a VoIPsession. At step 12-1, the mobile device receives the DRX controlparameters. At steps 11-2 and 12-2, the network and the mobile devicedetermine the first of the periods that the mobile device will have itsreceiver powered on. There are various methods for this that aredetailed below, but in each case it is advantageous that both thenetwork and mobile device make the same determination. For example, insome cases, the network defines the start time and signals this to themobile device. At step 11-3, the network transmits to the mobile device,starting with the first on period, in accordance with the DRX parametersafter which DRX control is active. Similarly, at step 12-3, the mobiledevice receives from the network, starting with the first on period, inaccordance with the DRX parameters.

Various specific methods for the network and mobile device to determinethe first on period will now be described.

A) Network Defines on Period, and Signals this to Mobile Device

A first method for the network and mobile device to determine the firston period will now be described with reference to FIG. 13. Thisflowchart includes steps executed by the network, and steps executed bythe mobile device. The method begins with the network defining the firston period at step 13-1. For example, in semi-persistent scheduling case,the network might define the first on period such that thepre-configured resource occurs during the first on period. At step 13-2,the network transmits signalling to the mobile device to indicate thefirst on period. Various examples are given below. At step 13-3, themobile device receives the signalling that indicates the first onperiod.

Absolute Value of Start Time.

In a first example of the network sending signalling to indicate thefirst on period, the network sends a signaling message to the mobiledevice that indicates in absolute terms the start time of the DRXcontrol. In some embodiments, this is sent together with the other DRXparameters in which case an additional message is not required. Thestart time of the DRX control identifies the start time of the first onperiod for the DRX control.

In a specific example, the start time can be represented by a layer 1sub-frame index or a layer 2 frame index. Transmission period is dividedinto layer 1 sub-frames having a duration known to both the network andmobile devices. Thus, reference to a specific layer 1 sub-frame will bea reference to a specific time. In some embodiments, layer 1 sub-framesare 1 ms in duration, but other values are possible, and more generallythe sub-frame duration is implementation specific. A layer 1 sub-frameindex is simply a reference to a specific layer 1 sub-frame. In someembodiments, the layer 1 sub-frame index is a cyclically repeatingindex, for example starting at zero, counting up to 4095, and thenstarting at zero again. In such a case, the start time signaled by wayof sub-frame index will refer to the next layer 1 sub-frame having thatindex.

Relative Value of Start Time

In a second example of the network sending signalling to indicate thefirst on period, the network sends a signaling message to the mobiledevice that indicates the start time of the DRX control in relativeterms. For example, the network may transmit signaling to the mobiledevice that includes an activation timer duration. The activation timerduration identifies the start of the DRX control relative to when thesignaling was sent or received, thereby indicating when the first onperiod will occur. The mobile device starts a timer, and when the timerreaches the activation timer duration, the DRX procedure starts. Thistimer might for example be represented in terms of number of layer-1sub-frames (for example number of TTIs (transmission time intervals), oran actual time value. In some embodiments, the activation timer durationis sent along with other DRX parameters.

B) Default Configuration

In another embodiment, the mobile device has a default configurationthat defines when the first on time will be. When a defaultconfiguration is employed, both the network and the mobile device needto be aware of the default configuration to be employed for a givenmobile device, and to act accordingly. This method for the network andmobile device determine the first on period will now be described withreference to FIG. 14. This flowchart includes steps executed by thenetwork, and steps executed by the mobile device. The method begins withthe network accessing default parameter(s) to determine the first onperiod at step 14-1. For example, the first on-duration may be definedby default to start with the sub-frame that aligns with thesemi-persistent resource. At step 14-2, the mobile device accessesdefault parameter(s) to determine the first on period. For example, themobile device may be configured by default to assume that the firston-duration starts with the sub-frame that aligns with thesemi-persistent resource. These default configurations arepre-configured at both the network (for example in an ENB) and themobile device.

In a first example of the default configuration approach, the start timeof the first on period is aligned with the first sub-frame in which themobile device is assigned a semi-persistent resource, following theassignment of that semi-persistent resource.

In a second example of the default configuration approach, the first onperiod always occurs at a certain sub-frame index. For example, usingthe example of 4096 layer-1 sub-frame indexes that cyclically repeat, agiven mobile device might be configured to have a first on periodfollowing sub-frame 400. In that case, after configuring the mobiledevice to with other DRX parameters, the first on period will occurfollowing the next occurrence of sub-frame 400.

Another Mobile Device

Referring now to FIG. 10, shown is a block diagram of another mobiledevice that may implement any of the mobile device methods describedherein. The mobile device 101 is shown with specific components forimplementing features similar to those of the mobile device 10 of FIG.2. It is to be understood that the mobile device 101 is shown with veryspecific details for example purposes only.

A processing device (a microprocessor 128) is shown schematically ascoupled between a keyboard 114 and a display 126. The microprocessor 128may be a specific example of the processor with features similar tothose of the processor 16 of the mobile device 10 shown in FIG. 2. Themicroprocessor 128 controls operation of the display 126, as well asoverall operation of the mobile device 101, in response to actuation ofkeys on the keyboard 114 by a user.

The mobile device 101 has a housing that may be elongated vertically, ormay take on other sizes and shapes (including clamshell housingstructures). The keyboard 114 may include a mode selection key, or otherhardware or software for switching between text entry and telephonyentry.

In addition to the microprocessor 128, other parts of the mobile device101 are shown schematically. These include: a communications subsystem170; a short-range communications subsystem 103; the keyboard 114 andthe display 126, along with other input/output devices including a setof LEDs 104, a set of auxiliary I/O devices 106, a serial port 108, aspeaker 111 and a microphone 112; as well as memory devices including aflash memory 116 and a Random Access Memory (RAM) 118; and various otherdevice subsystems 120. The mobile device 101 may have a battery 121 topower the active elements of the mobile device 101. The mobile device101 is in some embodiments a two-way radio frequency (RF) communicationdevice having voice and data communication capabilities. In addition,the mobile device 101 in some embodiments has the capability tocommunicate with other computer systems via the Internet.

Operating system software executed by the microprocessor 128 is in someembodiments stored in a persistent store, such as the flash memory 116,but may be stored in other types of memory devices, such as a read onlymemory (ROM) or similar storage element. In addition, system software,specific device applications, or parts thereof, may be temporarilyloaded into a volatile store, such as the RAM 118. Communication signalsreceived by the mobile device 101 may also be stored to the RAM 118.

The microprocessor 128, in addition to its operating system functions,enables execution of software applications on the mobile device 101. Apredetermined set of software applications that control basic deviceoperations, such as a voice communications module 130A and a datacommunications module 130B, may be installed on the mobile device 101during manufacture. In addition, a personal information manager (PIM)application module 130C may also be installed on the mobile device 101during manufacture. The PIM application is in some embodiments capableof organizing and managing data items, such as e-mail, calendar events,voice mails, appointments, and task items. The PIM application is alsoin some embodiments capable of sending and receiving data items via awireless network 110. In some embodiments, the data items managed by thePIM application are seamlessly integrated, synchronized and updated viathe wireless network 110 with the device user's corresponding data itemsstored or associated with a host computer system. As well, additionalsoftware modules, illustrated as another software module 130N, may beinstalled during manufacture. One or more of the modules130A,130B,130C,130N of the flash memory 116 can be configured forimplementing features similar to those of the radio manager 14 of themobile device 10 shown in FIG. 2.

Communication functions, including data and voice communications, areperformed through the communication subsystem 170, and possibly throughthe short-range communications subsystem 103. The communicationsubsystem 170 includes a receiver 150, a transmitter 152 and one or moreantennas, illustrated as a receive antenna 154 and a transmit antenna156. In addition, the communication subsystem 170 also includes aprocessing module, such as a digital signal processor (DSP) 158, andlocal oscillators (LOs) 160. The communication subsystem 170 having thetransmitter 152 and the receiver 150 is an implementation of a specificexample of the wireless access radio 12 of the mobile device 10 shown inFIG. 2. The specific design and implementation of the communicationsubsystem 170 is dependent upon the communication network in which themobile device 101 is intended to operate. For example, the communicationsubsystem 170 of the mobile device 101 may be designed to operate withthe Mobitex™, DataTAC™ or General Packet Radio Service (GPRS) mobiledata communication networks and also designed to operate with any of avariety of voice communication networks, such as Advanced Mobile PhoneService (AMPS), Time Division Multiple Access (TDMA), Code DivisionMultiple Access (CDMA), Personal Communications Service (PCS), GlobalSystem for Mobile Communications (GSM), etc. The communication subsystem170 may also be designed to operate with an 802.11 Wi-Fi network, and/oran 802.16 WiMAX network. Other types of data and voice networks, bothseparate and integrated, may also be utilized with the mobile device101.

Network access may vary depending upon the type of communication system.For example, in the Mobitex™ and DataTAC™ networks, mobile devices areregistered on the network using a unique Personal Identification Number(PIN) associated with each device. In GPRS networks, however, networkaccess is typically associated with a subscriber or user of a device. AGPRS device therefore typically has a subscriber identity module,commonly referred to as a Subscriber Identity Module (SIM) card, inorder to operate on a GPRS network.

When network registration or activation procedures have been completed,the mobile device 101 may send and receive communication signals overthe communication network 110. Signals received from the communicationnetwork 110 by the receive antenna 154 are routed to the receiver 150,which provides for signal amplification, frequency down conversion,filtering, channel selection, etc., and may also provide analog todigital conversion. Analog-to-digital conversion of the received signalallows the DSP 158 to perform more complex communication functions, suchas demodulation and decoding. In a similar manner, signals to betransmitted to the network 110 are processed (e.g., modulated andencoded) by the DSP 158 and are then provided to the transmitter 152 fordigital to analog conversion, frequency up conversion, filtering,amplification and transmission to the communication network 110 (ornetworks) via the transmit antenna 156.

In addition to processing communication signals, the DSP 158 providesfor control of the receiver 150 and the transmitter 152. For example,gains applied to communication signals in the receiver 150 and thetransmitter 152 may be adaptively controlled through automatic gaincontrol algorithms implemented in the DSP 158.

In a data communication mode, a received signal, such as a text messageor web page download, is processed by the communication subsystem 170and is input to the microprocessor 128. The received signal is thenfurther processed by the microprocessor 128 for an output to the display126, or alternatively to some other auxiliary I/O devices 106. A deviceuser may also compose data items, such as e-mail messages, using thekeyboard 114 and/or some other auxiliary I/O device 106, such as atouchpad, a rocker switch, a thumb-wheel, or some other type of inputdevice. The composed data items may then be transmitted over thecommunication network 110 via the communication subsystem 170.

In a voice communication mode, overall operation of the device issubstantially similar to the data communication mode, except thatreceived signals are output to a speaker 111, and signals fortransmission are generated by a microphone 112. Alternative voice oraudio I/O subsystems, such as a voice message recording subsystem, mayalso be implemented on the mobile device 101. In addition, the display126 may also be utilized in voice communication mode, for example, todisplay the identity of a calling party, the duration of a voice call,or other voice call related information.

The short-range communications subsystem 103 enables communicationbetween the mobile device 101 and other proximate systems or devices,which need not necessarily be similar devices. For example, theshort-range communications subsystem may include an infrared device andassociated circuits and components, or a Bluetooth™ communication moduleto provide for communication with similarly-enabled systems and devices.

Numerous modifications and variations of the present application arepossible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims, the applicationmay be practised otherwise than as specifically described herein.

I claim:
 1. A method comprising: configuring a mobile device to operatein a discontinuous reception (DRX) mode, wherein the DRX mode includesDRX sleep periods and DRX awake periods, wherein during each DRX awakeperiod the mobile device monitors, for a dynamically-allocated resource,a plurality of downlink layer 1 control channel elements (CCE's) in eachof a plurality of consecutive sub-frames of that DRX awake period; andtransmitting, by a network, signaling comprising a DRX control parameterthat indicates a first of said DRX awake periods.
 2. The method of claim1, further comprising transmitting, by the network, signaling comprisinga DRX control parameter that indicates an extension period during whichthe mobile device will continue to monitor a plurality of downlink layer1 CCE's following one of said DRX awake periods for a dynamic schedulingallocation.
 3. The method of claim 1, wherein the signaling indicatesthe first of said DRX awake periods in absolute terms.
 4. The method ofclaim 3, wherein the signaling indicating the first of said DRX awakeperiods in absolute terms comprises signaling that indicates a layer-1sub-frame index.
 5. The method of claim 1, wherein the signalingindicates the first of said DRX awake periods in relative terms.
 6. Themethod of claim 5 wherein the signaling indicating the first of said DRXawake periods in relative terms comprises signaling that indicates anactivation-timer duration.
 7. The method of claim 6 wherein transmittingthe activation-timer duration comprises at least one of: transmittingthe activation-timer duration in units of layer-1 sub-frames; ortransmitting the activation-timer duration in units of actual time.
 8. Abase station, comprising: one or more processors configured to:configure a mobile device to operate in a discontinuous reception (DRX)mode, wherein the DRX mode includes DRX sleep periods and DRX awakeperiods, wherein during each DRX awake period the mobile devicemonitors, for a dynamically-allocated resource, a plurality of downlinklayer 1 control channel elements (CCE's) in each of a plurality ofconsecutive sub-frames of that DRX awake period; and transmit signalingcomprising a DRX control parameter that indicates a first of said DRXawake periods.
 9. The base station of claim 8, the one or moreprocessors further configured to transmit signaling comprising a DRXcontrol parameter that indicates an extension period during which themobile device will continue to monitor a plurality of downlink layer 1CCE's following one of said DRX awake periods for a dynamic schedulingallocation.
 10. The base station of claim 8, wherein the signalingindicates the first of said DRX awake periods in absolute terms.
 11. Thebase station of claim 10, wherein the signaling indicating the first ofsaid DRX awake periods in absolute terms comprises signaling thatindicates a layer-1 sub-frame index.
 12. The base station of claim 8,wherein the signaling indicates the first of said DRX awake periods inrelative terms.
 13. The base station of claim 12, wherein the signalingindicating the first of said DRX awake periods in relative termscomprises signaling that indicates an activation-timer duration.
 14. Thebase station of claim 13, wherein the one or more processors configuredto transmit the activation-timer duration comprises the one or moreprocessors configured to at least one of: transmit the activation-timerduration in units of layer-1 sub-frames; or transmit theactivation-timer duration in units of actual time.
 15. A computerprogram product encoded on non-transitory medium, the product comprisingcomputer readable instructions for causing one or more processors toperform operations comprising: configuring a mobile device to operate ina discontinuous reception (DRX) mode, wherein the DRX mode includes DRXsleep periods and DRX awake periods, wherein during each DRX awakeperiod the mobile device monitors, for a dynamically-allocated resource,a plurality of downlink layer 1 control channel elements (CCE's) in eachof a plurality of consecutive sub-frames of that DRX awake period; andtransmitting, by a network, signaling comprising a DRX control parameterthat indicates a first of said DRX awake periods.
 16. The computerprogram product of claim 15, the instructions further comprisingtransmitting, by the network, signaling comprising a DRX controlparameter that indicates an extension period during which the mobiledevice will continue to monitor a plurality of downlink layer 1 CCE'sfollowing one of said DRX awake periods for a dynamic schedulingallocation.
 17. The computer program product of claim 15, wherein thesignaling indicates the first of said DRX awake periods in absoluteterms.
 18. The computer program product of claim 17, wherein thesignaling indicating the first of said DRX awake periods in absoluteterms comprises signaling that indicates a layer-1 sub-frame index. 19.The computer program product of claim 15, wherein the signalingindicates the first of said DRX awake periods in relative terms.
 20. Thecomputer program product of claim 19, wherein the signaling indicatingthe first of said DRX awake periods in relative terms comprisessignaling that indicates an activation-timer duration.
 21. The computerprogram product of claim 20, wherein the instructions comprisingtransmitting the activation-timer duration comprises instructionscomprising at least one of: transmitting the activation-timer durationin units of layer-1 sub-frames; or transmitting the activation-timerduration in units of actual time.